Numerical simulation of fluid flow and heat transfer in a diesel fuel heater

V podjetju Hidria d.o.o. (podružnica Tolmin) je v razvojni fazi grelnik dizelskega goriva. Ena od razvojnih zahtev kupca je bila tudi numerična simulacija pretoka nafte skozi grelnik. Zanimala nas je temperaturna in tlačna razlika med vhodnim in izhodnim stanjem goriva pri pretoku skozi grelnik. Numerični preračun smo naredili v programu ANSYS CFX. 3D model smo za mreženje in preračun pripravili v PTC Creo 3.0 modelirniku. Robne pogoje smo definirali v CFX-Pre modulu ANSYS-a. Rezultate numerične simulacije smo primerjali z izmerjenimi. Meritve smo izvedli v prostorih podjetja. Preračun in meritve so bile izvedene za tri časovno neodvisne (stacionarne) pretoke. Napako numeričnega preračuna smo ustrezno ovrednotili. Rezultate smo grafično predstavili v modulu CFX-Post. Prikazali smo hitrostno, temperaturno in tlačno stanje. Toplotni izkoristek grelnika je pri največjem pretoku znašal 90 %. Iz rezultatov in njihovega grafičnega prikaza smo izpostavili možnosti za izboljšave numeričnega modela in konstrukcije grelnika.In the company Hidria d.o.o. (branch of Tolmin) the diesel fuel heater is now in development stage. One of the customer development requirements was also a numerical simulation of fluid flow through the heater. We were interested in the temperature and pressure difference between the input and the output of fuel condition when it is flowing through the heater. We made a numerical simulation in the ANSYS CFX program. 3D model for meshing and later on for calculation, was prepared in CAD software called PTC Creo 3.0. Boundary conditions were defined in the CFX-Pre module of ANSYS. The results of the numerical simulation were compared with the measured ones. We carried out the measurements at the company’s premises. The calculations and measurements were made for three time-independent (stationary) flows. The numerical calculation errors of temperature and pressure difference were evaluated accordingly. We graphically presented the most trust worthy results in CFX-Post module. We’ve shown speed, temperature and pressure condition. Thermal efficiency of the heater at the maximum flowrate, amounted to 90 %. From the results and their graphical representation, we have highlighted the possibility of improving the numerical model and construction of the heater